                                (reductions msg-fn prev)
                                (into [] (comp cat (drop 1))))]
         (if (empty? output-series)
-          [(->Cached (:value prev))]
+          [(->Cached (value prev))]
           output-series)))))
 
 ; wiring up channels:

  be used as a fallback, and then two more values will be dropped before fresh
  values start being emitted."
  [xform base sig]
  (let [reducer ((comp (core/map :value)
                       xform
                       (core/map ->Fresh))
                 conj)

        msgs->events (comp cat
                           (filter fresh?)
                           (core/map (fn [msg]
                                       (->Event topic (value msg)))))
        events-channel-fn (fn [live-graph _]
                            (async/tap (get (:mult-map live-graph) source)
                                       (chan 1 msgs->events)))]
